And while Black Sabbath have been accumulating headlines almost daily with announcements about behind-the-scenes videos, tours, track debuts and Ozzy Osbourne's marital situation, Deep Purple and their new album have skulked in the shadows, waiting for just the right moment to strike.

That moment is now.

Now What?!, the band's 19th studio album, comes out this week, Tuesday, April 30, via Eagle Rock Entertainment. It is the fifth Deep Purple album to feature the fleet fretwork of Steve Morse, who can be heard on "Hell to Pay," one of two new tracks released by the band. The complete 2013 Deep Purple lineup is Ian Paice (drums), Roger Glover (bass), Ian Gillan (vocals), Steve Morse (guitar) and Don Airey (keyboards).

Which leads us to a question: What is the best Deep Purple song? Pick anything from the band's vast catalog, from "Smoke on the Water" to "Highway Star," "Woman from Tokyo," "Space Truckin'," "Perfect Strangers" and beyond. Vote for whatever you want, but please only vote once and only for a single song. And if you can't find your choice in the list below, feel free to write in your own choice.

We've also supplied a photo gallery of all 19 Deep Purple albums to help jog your memory. Check out the poll and photo gallery below!

For more information on the band, plus their tour dates, visit deeppurple2013.com. Follow them on Facebook here.